By Michael Hernandez

WASHINGTON

The U.S. retaliated Monday for a chemical attack in the U.K. blamed on Russia by expelling 60 diplomats Washington said were working as intelligence officers, and ordered the closure of Moscow’s consulate in Seattle. 

Those expelled include 48 embassy employees and 12 individuals who were working at the Russian mission to the UN, a senior administration official confirmed to reporters on condition of anonymity.

All are accused by the official of working as covert Russian intelligence officers under the diplomatic cover their posts afforded, and a separate official who was also taking part in the briefing called the number of Russian intelligence officers in the U.S. "unacceptably numerous".

All 60 have seven days to depart the U.S.

The Seattle consulate was shuttered due to its proximity to a U.S. submarine base, another official who spoke to reporters on condition he not be named said.

"Today’s actions make the United States safer by reducing Russia’s ability to spy on Americans and to conduct covert operations that threaten America’s national security," White House spokeswoman Sarah Huckabee Sanders said in a statement.

The actions are some of the strongest pushback to date from the Donald Trump administration on Russia after Moscow was accused of a series of activities aimed at undermining the West, including alleged interference in the U.S.'s 2016 presidential election. 

Most recently, former Russian spy Sergei Skripal, 66, and his daughter Yulia, 33, were admitted to a hospital March 4 after being found unconscious in the southern English city of Salisbury. British officials have placed blame squarely with Russia, a charge Vladimir Putin adamantly denies. 

London has said the attack was carried out using a Soviet-era Cold War nerve agent from a family called Novichok. 

Skripal was granted refuge in the UK following a 2010 spy exchange between the U.S. and Russia. Before the exchange, he was serving 13 years in prison for leaking information to British intelligence.

Last week, following an EU summit in Brussels, the U.K., Germany, and France reaffirmed the Russian state was responsible for the nerve agent poisoning of Skripal and his daughter.

"Beyond Russia’s destabilizing behavior across the world, such as its participation in the atrocities in Syria and its illegal actions in Ukraine, it has now used a chemical weapon within the borders of one of our closest allies," U.S. ambassador to the UN Nikki Haley said in a statement.

"Here in New York, Russia uses the United Nations as a safe haven for dangerous activities within our own borders. Today, the United States and many of our friends are sending a clear message that we will not stand for Russia’s misconduct," she added.

In Canada, that government expelled Russian diplomats Monday to protect “Canada security.”

Foreign Affairs Minister Chrystia Freeland said four diplomatic staff at the Russian embassy in the Canadian capital of Ottawa or the consulate general in Montreal will be ordered out of the country.

“The four have been identified as intelligence officers or individuals who have used their diplomatic status to undermine Canada’s security or interfere in our democracy,” Freeland said. “These measures are not aimed at the Russian people, with whom Canadians have long and fruitful ties. Canada remains committed to dialogue and co-operation with Russia on issues where we face common challenges.”

She added that the expulsion was also prompted to show “solidarity” with the U.K. for the nerve attack in Salisbury.

“The nerve gas attack in Salisbury, on the soil of Canada’s close partner and ally, is a despicable, heinous and reckless act, potentially endangering the lives of hundreds,” Freeland said in a statement.

A Russian request to add three additional staff in Canada was denied, Freeland said.

The moves by the U.S. and Canada were part of a wider effort with their European allies who expelled 14 dozens of Russian diplomats in an orchestrated reaction Monday for the Skripals’ poisoning.

At least 43 Russian diplomats have been expelled from EU member states. 

"As a direct follow up to last week’s European Council decision to react to Russia within a common framework, already today 14 member states have decided to expel Russian diplomats," said European Council President Donald Tusk, who was in Varna, Bulgaria for an EU-Turkey Summit.

And 13 Russian diplomats were expelled In Ukraine, a country that is not part of the EU, but which has been a flashpoint between Russia and the West since Russia annexed the Crimean Peninsula and propped up separatist rebels in that country's east. 

* Barry Ellsworth in Canada contributed to this report.